But don’t use the WD-40 in the lock itself. If the WD-40 works, I would not be surprised if you later find it will come back, which just means it needs a better cleaning and a good re-lube. (WD-40 is not a good lube)

That’s not the door ajar chime. That’s the SRS bulb out chime. Your airbag light is burnt out, or there’s something else wrong with the bulb circuit. There’s also something wrong with the SRS. Let me guess. The warning light has been on for so long that it burned out. Could this be it?